Examination of magnetic media is enhanced by the viewing of magnetization patterns.
U.S. Pat. No. 4,032,980, entitled “RECORDED MAGNETIC MEMBER VIEWING APPARATUS,” discloses a device for viewing magnetic images on magnetizable recording members. The device includes ferrofluid and metal flakes between transparent substrates. The present invention neither includes a ferrofluid nor metal flakes. U.S. Pat. No. 4,032,980 is hereby incorporated by reference into the specification of the present invention.
U.S. Pat. No. 4,101,905, entitled “METHOD FOR WRITING AND VIEWING MAGNETIC HUMAN READABLE CHARACTERS AND VIEWING MEANS THEREFOR,” discloses a device for and method of magnetically recording information in human readable form and viewing the same using encapsulated ferromagnetic particles. The present invention neither magnetically records information in human readable form nor uses encapsulated ferromagnetic particles to read the same. U.S. Pat. No. 4,101,905 is hereby incorporated by reference into the specification of the present invention.
U.S. Pat. No. 5,034,754, entitled “MAGNETIC PATTERN VIEWER,” discloses a device for visually displaying magnetic patterns using magnetic particles suspended in liquid. The present invention does not view magnetic patterns using magnetic particles suspended in a liquid. U.S. Pat. No. 5,034,754 is hereby incorporated by reference into the specification of the present invention.
U.S. Pat. No. 5,543,911, entitled “METHOD OF CURRENCY OR DOCUMENT VALIDATION BY USE OF AN ANTI-COUNTERFEITING MAGNETIC VIEWING STRIP,” discloses a method of authenticating currency or documents by adding magnetic material in the form of encapsulated nickel flakes suspended in fluid to the currency or document, moving a magnet in the vicinity of the added material, and noting whether or not light patterns reflected from the added material change in response to the movement of the magnet. The present invention does not use nickel flakes suspended in fluid. U.S. Pat. No. 5,543,911 is hereby incorporated by reference into the specification of the present invention.
U.S. Pat. No. 5,565,772, entitled “HIGH SENSITIVITY MAGNETIC VIEWER USING ANHYSTERETIC TRANSFER FOR VIEWING WEAR MAGNETIC PATTERNS,” discloses a device for viewing weak magnetic fields of around 1 Oe by applying an alternating current (AC) magnetic field of more than 100 Oe, which is then slowly reduced to zero, to bismuth-garnet on a transparent substrate while a small direct current (DC) bias field is applied. The present invention neither uses an AC magnetic field nor a DC bias field to view magnetic patterns. U.S. Pat. No. 5,565,772 is hereby incorporated by reference into the specification of the present invention.